Aquinas (a-kwī´nas; i.e. of Aquino), St. Thomas, a celebrated scholastic divine, born in 1225 or 1227, most probably at the castle of Rocco Secca, near Aquino. His father was Count of Aquino, in the kingdom of Naples. He was educated at the Benedictine monastery of Monte Casino, and at the University of Naples, where he studied for six years. About the age of seventeen he entered a convent of Dominicans, much against the wishes of his family. He attended the lectures of Albertus Magnus at Cologne, in whose company he visited Paris in 1245 or 1246. Here he became involved in the dispute between the university and the Begging Friars as to the liberty of teaching, advocating the rights claimed by the latter with great energy. In 1257 he received the degree of doctor from the Sorbonne, and began to lecture on theology, rapidly acquiring the highest reputation. In 1263 he is found at the Chapter of the Dominicans in London. In 1268 he was in Italy, lecturing in Rome, Bologna, and elsewhere. In 1271 he was again in Paris lecturing to the students; in 1272 he was professor at Naples. In 1263 he had been offered the archbishopric of Naples by Clement IV, but refused the offer. He died, in 1274, on his way to Lyons to attend a general council for the purpose of uniting the Greek and Latin Churches. He was called, after the fashion of the times, the angelic doctor, and was canonized by John XXII. The most important of his numerous works, which are all written in Latin, are the Summa Theologica,

which, although only professing to treat of theology, is in reality a complete and systematic summary of the knowledge of the time, and the Summa Philosophica. The work of St. Thomas consisted in an effort to harmonize the new scientific teachings of the age—derived from Arabian and Byzantine sources—with the doctrine of the Church, and to refute heresy. His disciples were known as Thomists. See Thomism.—Cf. P. Conway, St. Thomas Aquinas; and article in Hastings' Encyclopedia of Religion and Ethics.

Aquita´nia, later Aquitaine, a Roman province in Gaul, which comprehended the countries on the coast from the Garonne to the Pyrenees, and from the sea to Toulouse. It was brought into connection with England by the marriage of Henry II with Eleanor, daughter of the last Duke of Aquitaine. The title to the province was for long disputed by England and France, but it was finally secured by the latter (1453).

Arabah´, a deep rocky valley or depression in north-western Arabia, between the Dead Sea and Gulf of Akabah, a sort of continuation of the Jordan valley.

Arabesque (ar´a-besk), a species of ornamentation for enriching flat surfaces, often consisting of fanciful figures, human or animal, combined with floral forms. There may be said to be three periods and distinctive varieties of arabesque—(a) the Roman or Græco-Roman, introduced into Rome from the East when pure art was declining; (b) the Arabesque of the Moors as seen in the Alhambra, introduced by them into Europe in the Middle Ages; (c) Modern Arabesque, which took its rise in Italy in the Renaissance period of art. The arabesques of the Moors, who are prohibited by their religion from representing animal forms, consist essentially of complicated ornamental designs based on the suggestion of plant-growth, combined with extremely complex geometrical forms.

Arabgir (a˙-ra˙b-gēr´), or Arabkir´, a town in Asia, 147 miles W.S.W. of Erzerum, noted for its manufacture of silk and cotton goods. Pop. between 20,000 and 30,000.

Ara´bia, a vast peninsula in the S.W. of Asia, bounded on the N. by the great Syro-Babylonian plain, N.E. by the Persian Gulf and the Sea of Oman, S. or S.E. by the Indian Ocean, and S.W. by the Red Sea and Gulf of Suez. Its length from N.W. to S.E. is about 1800 miles, its mean breadth about 600 miles, its area approximately 1,200,000 sq. miles, its population probably less than 5,000,000. Roughly described, it exhibits a central table-land surrounded by a series of deserts, with numerous scattered oases, while around this is a line of mountains parallel to and approaching the coasts, and with a narrow rim of low grounds (tehāma) between them and the sea. In its general features Arabia resembles the Sahara, of which it may be considered a continuation. Like the Sahara, it has its wastes of loose sand, its stretches of bare rocks and stones, its mountains devoid of vegetation, its oases with their wells and streams, their palm-groves and cultivated fields—islands of green amidst the surrounding desolation. Rivers proper there are none. By the ancients the whole peninsula was broadly divided into three great sections—Arabia Petræa (containing the city Petra), Deserta (desert), and Felix (happy). The first and last of these answer roughly to the modern divisions of the region of Sinai in the N.W. and Yemen in the S.W., while the name Deserta was vaguely given to the rest of the country. (See Explorations, Modern.) The principal divisions at the present are Madian in the north-west; south of this, Hejaz, Assir, and Yemen, all on the Red Sea, the last named occupying the south-western part of the peninsula, and comprising a tehāma or maritime lowland on the shores of the Red Sea, with an elevated inland district of considerable breadth; Hadramaut on the south coast; Oman occupying the south-east angle; El-Hasa and Koveït on the Persian Gulf; El-Hamad (Desert of Syria), Nefûd, and Jebel Shammar in the north; Nejd, the Central Highlands, which occupies a great part of the interior of the country, while south of it is the great unexplored Dahkna or sandy desert. Between 1902-5 a joint commission of British and Turkish officers laid down a boundary line defining the limits between Turkish territory and that of the independent Arab tribes in political relations with Great Britain. Nearly the whole of Southern Arabia came within the sphere of British influence. Madian belongs to Egypt; the Hejaz, Yemen, Bahr-el-Hasa, Koveït, &c., were more or less under the suzerainty of Turkey until 1914. The rest of the country is ruled by independent chiefs—sheikhs, emirs, and imâms—while the title of sultan has been assumed by the chief of the Wahabis in Nejd, the sovereign of Oman (who has a subsidy from the Indian Government), and some petty princes in the south of the peninsula. On 9th June, 1916, the Grand Shereef of Mecca declared himself independent of the Turkish Government, and an Arab revolt spread rapidly. The Grand Shereef Hussein then announced to the Moslem world that the Shereefate of Mecca was henceforth independent, and on 4th Nov., 1916, he had himself formally proclaimed King, or Sultan, of Arabia. The status of the whole of Arabia was determined by the Peace Conference. (See Hejaz, Mesopotamia, Syria, Sykes-Picot Treaty.) The chief towns are Mecca, the birthplace of Mahomet; Medina, the place to which he fled from Mecca (A.D. 622), and where he is buried; Hodeida, a seaport exporting Mocha coffee;

Aden, on the S.W. coast, belonging to Britain; Sana, the capital of Yemen; and Muscat, the capital of Oman. The chief towns of the interior are Haïl, the residence of the Emir of Jebel Shammar; Oneizah, under the same ruler; and Rijadh, capital of Nejd and Hasa. The most flourishing portions of Arabia are in Oman, Hadramaut, and Nejd. In the two former are localities with numerous towns and villages and settled industrious populations like that of India or Europe.

The climate of Arabia in general is marked by extreme heat and dryness. Aridity and barrenness characterize both high and low grounds, and the date-palm is often the only representative of vegetable existence. There are districts which in the course of the year are hardly refreshed by a single shower of rain. Forests there are few or none. Grassy pastures have their place supplied by steppe-like tracts, which are covered for a short season with aromatic herbs, serving as food for cattle. The date-palm furnishes the staple article of food; the cereals are wheat, barley, maize, and millet; various sorts of fruit flourish; coffee and many aromatic plants and substances, such as gum-arabic, benzoin, mastic, balsam, aloes, myrrh, frankincense, &c., are produced. There are also cultivated in different parts of the peninsula, according to the soil and climate, beans, rice, lentils, tobacco, melons, saffron, colocynth, poppies, olives, &c. Sheep, goats, oxen, the horse, the camel, ass, and mule supply man's domestic and personal wants. Among wild animals are gazelles, ostriches, the lion, panther, hyena, jackal, &c. Among mineral products are saltpetre, mineral pitch, petroleum, salt, sulphur, and several precious stones, as the carnelian, agate, and onyx. The people of Arabia, according to their own traditions, are derived from two stocks, the pure Arabs and the naturalized Arabs or Mustarab. They are leading either a settled agricultural life or a nomadic existence. In Southern Arabia the Jews form a large element in the towns' population. Commerce is largely in the hands of foreigners, among whom the Jews and Banians (Indian merchants) are the most numerous.

The history of Arabia previous to Mahomet is obscure. The earliest inhabitants are believed to have been of the Semitic race. Jews in great numbers migrated into Arabia after the destruction of Jerusalem, and, making numerous proselytes, indirectly favoured the introduction of the doctrines of Mahomet. With his advent the Arabians revolted and united for the purpose of extending the new creed; and under the caliphs—the successors of Mahomet—they attained great power, and founded large and powerful kingdoms in three continents. (See Caliphs.) On the fall of the caliphate of Bagdad in 1258 the decline set in, and on the expulsion of the Moors from Spain the foreign rule of the Arabs came to an end. In the sixteenth century Turkey subdued Hejaz and Yemen, and received the nominal submission of the tribes inhabiting the rest of Arabia. The allegiance of Hejaz was renounced early in the European War; but Yemen achieved its independence in the seventeenth century, and maintained it till 1871, when the territory again fell into the hands of the Turks. In 1839 Aden was occupied by the British. Oman early became virtually independent of the caliphs, and grew into a well-organized kingdom. In 1507 its capital, Maskat or Muscat, was occupied by the Portuguese, who were not driven out till 1659. The Wahabis appeared towards the end of the eighteenth century, and took an important part in the political affairs of Arabia, but their progress was interrupted by Mohammed Ali, pasha of Egypt, and they suffered a complete defeat by Ibrahim Pasha. He extended his power over most of the country, but the events of 1840 in Syria compelled him to renounce all claims to Arabia. The Hejaz thus again became subject to Turkish sway, and until 1914 Turkey continually extended its rule not only over Yemen, but also over the district of El-Hasa on the Persian Gulf.—Bibliography: Sir R. F. Burton, Pilgrimage to Medina and Mecca; E. Reclus, Les Arabes; C. M. Doughty, Arabia Deserta, and Wanderings in Arabia; G. W. Bury, Arabia Infelix; S. M. Zwemer, Arabia, the Cradle of Islam.